Incontinence is a major health problem in the United States and accounts for approximately $10 billion of our annual health care costs. It is estimated that over 10 million individuals suffer from urinary incontinence, 60-70% of which are females. Although there are several types of female incontinence, stress incontinence or stress and urge incontinence is the most common. Stress incontinence is triggered by sudden tensing of the abdominal muscles which occurs during coughing, laughing and certain physical activities. It is caused by abnormalities in the anatomy of the bladder outlet structures, the sphincter and urethra. This problem is most pronounced in the elderly female population due to prolapse of the uterus which distorts the geometry of the bladder neck resulting in a 30% incontinence rate in women over 60 years of age. This problem causes acute embarrassment and inhibits physical and social activity.
Many methods and devices for managing incontinence are currently available. In younger patients, surgery is the method of choice for severe incontinence. However, in older individuals, the risk of complications makes this option impractical. In addition, in mild cases, surgery is not a desirable option. Another common method of managing incontinence is the use of an absorbent pad placed over the urethral opening which is nonhygienic, uncomfortable and does not prevent the involuntary urination. Other less effective incontinence treatment methods include pharmacotherapy, exercise, electrical stimulation and periurethral injections.
Incontinence devices disclosed in the prior art rely mainly on urethral occlusion. Nielsen et al. (J. Urol., (1990) 144:1199-1202) and U.S. Pat. No. 5,082,006 to Jonasson disclose an incontinence device having a shaft with one or more knobs placed along the shaft which occludes the urethra. This design relies on the presence of at least one knob inside the urethra at all times which represents a source of continuous irritation to the patient. In addition, the constant pressure exerted on the walls of the urethra over time will cause urethral dilation, resulting in leakage of urine around the device. This urethral dilation can allow expulsion of the device due to increased bladder pressure, resulting in incontinence.
U.S. Pat. No. 5,090,424 to Simon et al. discloses a flexible urethral plug consisting of a soft inflatable plastic catheter and a transportable liquid. The fluid is introduced through a check valve to inflate the device within the urethra, the bladder neck or the bladder. This device is cumbersome and, since it contains a chamber and a valve, it is impossible to prevent bacterial colonization of the device leading to possible urinary tract infection. In addition, the chamber and valve can malfunction, resulting in balloon deflation and potential leakage of urine. Valve malfunction can also cause either expulsion of the device, resulting in incontinence, or retention of the device which will require medical intervention for its removal.
U.S. Pat. No. 3,372,695 to Beliveau et al. describes an incontinence device having a rod with two retainer portions extending into the bladder to keep the device in position. The continence mechanism of this device is the rod only which will lose its occlusive action over time due to urethral dilation, resulting in leakage of urine around the rod. In addition, this device will irritate the urethra and, since it has moving parts which are impossible to keep clean, there is a risk of bacterial growth and the potential for urinary tract infection. Moreover, valve malfunction can result in either expulsion or retention of the device. U.S. Pat. No. 3,797,478 to Walsh et al. discloses an incontinence device having two inflatable collars and an inflatable stem. Since the inflatable stem occludes and applies constant pressure on the urethra, this will result in urethral wall relaxation and leakage around the device. Moreover, this device requires the use of a syringe to inflate and deflate the collars and stem, making it difficult to use, especially by patients with arthritis. In addition, it is difficult to keep the device free of bacteria.
U.S. Pat. Nos. 3,646,929 to Bonnar and 4,920,986 to Biswas teach intravaginal incontinence devices which can expand to exert pressure on the bladder neck, thus restricting the flow of urine. These methods do not rely on occluding the bladder via insertion of a device into the urethra.
There is a need for a female incontinence device which is simple to use, easy to manufacture, easy to clean and which will not cause irritation to either the urethra or the bladder.